Combined taurine, epigallocatechin gallate and genistein therapy reduces HSC-T6 cell proliferation and modulates the expression of fibrogenic factors

A guide to pathophysiology, signaling pathways, and preclinical models of liver fibrosis

Liver fibrosis is potentially a reversible form of liver disease that evolved from the early stage of liver scarring as a consequence of chronic liver injuries. Recurrent injuries in the liver without any appropriate medication cause the injuries to get intense and deeper, which gradually leads to the progression of irreversible cirrhosis or carcinoma. Unfortunately, there are no approved treatment strategies for reversing hepatic fibrosis, making it one of the significant risk factors for developing advanced liver disorders and liver disease-associated mortality. Consequently, the interpretation of the fundamental mechanisms, etiology, and pathogenesis is crucial for identifying the potential therapeutic target as well as evaluating novel anti-fibrotic therapy. However, despite innumerable research, the functional mechanism and disease characteristics are still obscure. To accelerate the understanding of underlying disease pathophysiology, molecular pathways and disease progression mechanism, it is crucial to mimic human liver disease through the formation of precise disease models. Although various in vitro and in vivo liver fibrotic models have emerged and developed already, a perfect clinical model replicating human liver diseases is yet to be established, which is one of the major challenges in discovering proper therapeutics. This review paper will shed light on pathophysiology, signaling pathways, preclinical models of liver fibrosis, and their limitations.

Puerarin: a hepatoprotective drug from bench to bedside

Pueraria is a time-honored food and medicinal plant, which is widely used in China. Puerarin, the main component extracted from pueraria, has a variety of pharmacological characteristics. In recent years, puerarin has received increasing attention for its significant hepatoprotective effects, such as metabolic dysfunction-associated steatotic liver disease, alcohol-related liver disease, and hepatic carcinoma. This paper explores the pharmacological effects of puerarin on various liver diseases through multiple mechanisms, including inflammation factors, oxidative stress, lipid metabolism, apoptosis, and autophagy. Due to its restricted solubility, pharmacokinetic studies revealed that puerarin has a low bioavailability. However, combining puerarin with novel drug delivery systems can improve its bioavailability. Meanwhile, puerarin has very low toxicity and high safety, providing a solid foundation for its further. In addition, this paper discusses puerarin's clinical trials, highlighting its unique advantages. Given its excellent pharmacological effects, puerarin is expected to be a potential drug for the treatment of various liver diseases.

Extracellular matrix turnover: phytochemicals target and modulate the dual role of matrix metalloproteinases (MMPs) in liver fibrosis

Extracellular matrix (ECM) resolution by matrix metalloproteinases (MMPs) is a well-documented mechanism. MMPs play a dual and complex role in modulating ECM degradation at different stages of liver fibrosis, depending on the timing and levels of their expression. Increased MMP-1 combats disease progression by cleaving the fibrillar ECM. Activated hepatic stellate cells (HSCs) increase expression of MMP-2, -9, and -13 in different chemicals-induced animal models, which may alleviate or worsen disease progression based on animal models and the stage of liver fibrosis. In the early stage, elevated expression of certain MMPs may damage surrounding tissue and activate HSCs, promoting fibrosis progression. At the later stage, downregulation of MMPs can facilitate ECM accumulation and disease progression. A number of phytochemicals modulate MMP activity and ECM turnover, alleviating disease progression. However, the effects of phytochemicals on the expression of different MMPs are variable and may depend on the disease models and stage, and the dosage, timing and duration of phytochemicals used in each study. Here, we review the most recent advances in the role of MMPs in the effects of phytochemicals on liver fibrogenesis, which indicates that further studies are warranted to confirm and define the potential clinical efficacy of these phytochemicals.

Preventive Effect and Mechanism of Anthocyanins from Aronia Melanocarpa Elliot on Hepatic Fibrosis Through TGF-β/Smad Signaling Pathway

In order to explore the effect and mechanism of Aornia mealnocarpa Elliot anthocyanins (AMA) at the cellular level on hepatic fibrosis (HF), molecular docking, RT-PCR and Western Blotting were used to explore the molecular mechanism and the effects of different doses AMA on HSC-T6 cells by TGF-β1 induction. The results showed that the binding energy of anthocyanins on TGF-β1 (PDB ID: 3KFD) was in the range of -9.5 to 8.6 kcal/mol, with good low energy parameters and binding positions. AMA could effectively inhibit the expressions of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total serum bilirubin (TSB), and improved the expressions of total protein (TP) and albumin (ALB). RT-PCR and Western bloting results showed that AMA could inhibited the secretion of inflammatory cytokines IL-1, IL-6, TNF-α and COX-2, and inhibit the expression of TGF-β1, P-Smad2, α-SMA and Collagen I in TGF-β /Smad signaling pathway. This study revealed the AMA's inhibition effects and mechanism of malignant biological behavior of HSC-T6 cells, in order to provide theoretical basis for the prevention and treatment of HF by Aronia melanocarpa Elliot.

Correction: Yan, L., et al. Combined Taurine, Epigallocatechin Gallate and Genistein Therapy Reduces HSC-T6 Cell Proliferation and Modulates the Expression of Fibrogenic Factors. Int. J. Mol. Sci. 2013, 14, 20543-20554

The authors regret that, during the preparation of our published manuscript "Combined taurine, epigallocatechin gallate and genistein therapy reduces HSC-T6 cell proliferation and modulates the expression of fibrogenic factors" [...].

A Comprehensive Review of Natural Products against Liver Fibrosis: Flavonoids, Quinones, Lignans, Phenols, and Acids

Liver fibrosis resulting from continuous long-term hepatic damage represents a heavy burden worldwide. Liver fibrosis is recognized as a complicated pathogenic mechanism with extracellular matrix (ECM) accumulation and hepatic stellate cell (HSC) activation. A series of drugs demonstrate significant antifibrotic activity in vitro and in vivo. No specific agents with ideally clinical efficacy for liver fibrosis treatment have been developed. In this review, we summarized the antifibrotic effects and molecular mechanisms of 29 kinds of common natural products. The mechanism of these compounds is correlated with anti-inflammatory, antiapoptotic, and antifibrotic activities. Moreover, parenchymal hepatic cell survival, HSC deactivation, and ECM degradation by interfering with multiple targets and signaling pathways are also involved in the antifibrotic effects of these compounds. However, there remain two bottlenecks for clinical breakthroughs. The low bioavailability of natural products should be improved, and the combined application of two or more compounds should be investigated for more prominent pharmacological effects. In summary, exploration on natural products against liver fibrosis is becoming increasingly extensive. Therefore, natural products are potential resources for the development of agents to treat liver fibrosis.

ASIC1a inhibits cell pyroptosis induced by acid-induced activation of rat hepatic stellate cells

The activation of hepatic stellate cells (HSCs) is associated with liver fibrosis, the pathological feature of most forms of chronic hepatic damage, and is accompanied by abnormal deposition of the extracellular matrix (ECM). During the pathological process, acid-sensing ion channel 1a (ASIC1a), which is responsible for Ca2+ transportation, is involved in the activation of HSCs. It has previously been identified that ASIC1a is related to pyroptosis in articular chondrocytes. However, it remains unclear whether ASIC1a restrains pyroptosis during liver fibrosis. Here, we determined that the levels of pyroptosis-associated speck-like protein, gasdermin D, caspase-1, nucleotide-binding oligomerization domain (NOD)-like receptor 3, and apoptosis-associated speck-like protein (ASC) decreased, while the level of α-smooth muscle actin and collagen-I increased upon introduction of ASIC1a into an acid-induced model. Inhibition or silencing of ASIC1a and the use of Ca2+ -free medium were able to promote the pyroptosis of activated HSCs, which reduced their deposition. In summary, our study indicates that ASIC1a inhibits pyroptosis of HSCs and that inhibition of ASIC1a may be able to promote pyroptosis to relieve liver fibrosis.

Anti-fibrosis activity of combination therapy with epigallocatechin gallate, taurine and genistein by regulating glycolysis, gluconeogenesis, and ribosomal and lysosomal signaling pathways in HSC-T6 cells

A previous study by our group indicated that combined treatment with taurine, epigallocatechin gallate (EGCG) and genistein protects against liver fibrosis. The aim of the present study was to elucidate the antifibrotic mechanism of this combination treatment using isobaric tag for relative and absolute quantification (iTRAQ)-based proteomics in an activated rat hepatic stellate cell (HSC) line. In the present study, HSC-T6 cells were incubated with taurine, EGCG and genistein, and cellular proteins were extracted and processed for iTRAQ labeling. Quantification and identification of proteins was performed using two-dimensional liquid chromatography coupled with tandem mass spectrometry. Proteomic analysis indicated that the expression of 166 proteins were significantly altered in response to combination treatment with taurine, EGCG and genistein. A total 76 of these proteins were upregulated and 90 were downregulated. Differentially expressed proteins were grouped according to their association with specific Kyoto Encyclopedia of Genes and Genomes pathways. The results indicated that the differentially expressed proteins hexokinase-2 and lysosome-associated membrane glycoprotein 1 were associated with glycolysis, gluconeogenesis and lysosome signaling pathways. The expression of these proteins was validated using western blot analysis; the expression of hexokinase-2 was significantly decreased and the expression of lysosome-associated membrane glycoprotein 1 was significantly increased in HSC-T6 cells treated with taurine, EGCG and genistein compared with the control, respectively (P<0.05). These results were in accordance with the changes in protein expression identified using the iTRAQ approach. Therefore, the antifibrotic effect of combined therapy with taurine, EGCG and genistein may be associated with the activation of several pathways in HSCs, including glycolysis, gluconeogenesis, and the ribosome and lysosome signaling pathways. The differentially expressed proteins identified in the current study may be useful for treatment of liver fibrosis in the future.

Genistein improves schistosomiasis liver granuloma and fibrosis via dampening NF-kB signaling in mice

In schistosomiasis, egg deposition in the liver contributes to the formation of hepatic granuloma and fibrosis, which are the most serious clinical pathological features. It has been proposed that activation of the nuclear factor kappa B (NF-κB) signaling pathways is closely associated with the development of hepatic granuloma and fibrosis. Genistein has been shown to inhibit the activity of NF-κB signaling pathways, which might be a potential agent to protect against Schistosoma japonicum egg-induced liver granuloma and fibrosis. In this study, liver granuloma and fibrosis were induced by infecting BALB/c mice with 18 ± 3 cercariae of S. japonicum. At the beginning of egg granuloma formation (early phase genistein treatment from 4 to 6 weeks after infection) or after the formation of liver fibrosis (late phase genistein treatment from 6 to 10 weeks after infection), the infected mice were injected with genistein (25, 50 mg/kg). The results revealed that genistein treatment significantly decreased the extent of hepatic granuloma and fibrosis in infected mice. The activity of NF-κB signaling declined sharply after the treatment with genistein, as evidenced by the inhibition of NF-κB-p65, phospho-NF-κB-p65, and phospo-IκB-α expressions, as well as the expression of IκB-α and the messenger RNA (mRNA) expression of inflammatory cytokines (MCP1, TNFα, IL1β, IL4, IL10) mediated by NF-κB signaling pathways in the early phase of the infection. Moreover, western blot and immunohistochemistry assays demonstrated that the contents of α-smooth muscle actin (α-SMA) and transforming growth factor-β were dramatically reduced in liver tissue under the treatment of genistein in the late phase of the infection. At the same time, the mRNA expression of MCP1, TNFα, and IL10 was inhibited markedly. These results provided evidence that genistein reduces S. japonicum egg-induced liver granuloma and fibrosis, at least partly due to decreased NF-κB signaling, and subsequently decreased MCP1, TNFα, and IL10 expressions. This implies that genistein can be a potential natural agent against schistosomiasis.

Txn1, Ctsd and Cdk4 are key proteins of combination therapy with taurine, epigallocatechin gallate and genistein against liver fibrosis in rats

The anti-fibrotic mechanism of combination therapy with taurine, epigallocatechin gallate and genistein was studied from the perspective of serum proteomics in our previous work. In order to further investigate and systematically analyse other possible therapeutic mechanism of combination therapy against liver fibrosis, isobaric tags for relative and absolute quantification (iTRAQ) proteomic analysis was applied to study the protein profile changes in liver tissue of carbon tetrachloride-induced liver fibrosis rats after combination therapy. A total of 115 differentially expressed proteins containing 84 up-regulated and 31 down-regulated proteins in response to combination therapy were identified. Three differentially expressed proteins (Txn1, Ctsd and Cdk4) involved in antioxidant defense system and the activation and proliferation of hepatic stellate cell were selected for further validation by western blot and real-time PCR analysis. Our study highlight the importance of differentially expressed proteins Txn1, Ctsd and Cdk4 against liver fibrosis, which may provide a more precise and comprehensive perspective for clarifying the roles of combination therapy as a potential agent for treatment of liver fibrosis.

Comparison of the therapeutic effectiveness of human CD34+ and rat bone marrow mesenchymal stem cells on improvement of experimental liver fibrosis in Wistar rats

BACKGROUND AND OBJECTIVE

Human umbilical cord blood (UCB) cells and bone marrow mesenchymal stem cells (BM-MSCs) have numerous advantages as grafts for cell transplantation. We hypothesized differing impacts of human UCB cells and rat BM-MSCs on reversal of hepatic injury and revival of liver function in carbon tetrachloride (CCl₄)-induced liver fibrosis.

METHODS

Forty rats were divided into 4 groups; control group, CCl₄ group, CCl₄/CD34⁺ group and CCl₄/BM-MSCs group. Blood samples were driven from rats at 4, 8 and 12 weeks to measure serum concentration of albumin and alanine aminotransferase (ALT). Quantitative expression of collagen Iα, TGF-β, α-SMA, albumin, MMP-2, MMP-9 and TNF-α were assessed by polymerase chain reaction. Histopathological examination of the liver tissue was performed. GFP labeled cells were detected in groups injected with stem cells.

RESULTS

Regarding liver function, CD34⁺ were more efficient than BM-MSCs in elevating albumin (P<0.05) and reducing ALT (P<0.05) concentrations. Concerning gene expression, CD34⁺ were more effective than BM-MSCs in reducing gene expressions of collagen Iα (P<0.01), TGF-β1 (P<0.01) and α-SMA (P<0.01). Both CD34⁺ and BM-MSCs have the same efficacy in reducing TNF-α (P<0.001 and P<0.01, respectively). Furthermore, CD34⁺ were more valuable than BM-MSCs in increasing gene expression of albumin (P<0.05) and MMP-9 (P<0.01).

CONCLUSION

Taken together; human UCB CD34⁺ stem cells were more efficient in improvement of experimental liver injury than BM-MSCs. This study highlighted an important role of human UCB CD34⁺ stem cells in liver fibrosis therapy.

Taurine drinking ameliorates hepatic granuloma and fibrosis in mice infected with Schistosoma japonicum

In schistosomiasis, egg-induced hepatic granuloma formation is a cytokine-mediated, predominantly CD4⁺ Th2 immune response that can give rise to hepatic fibrosis. Hepatic fibrosis is the main cause of increased morbidity and mortality in humans with schistosome infection. Taurine has various physiological functions and hepatoprotective properties as well as anti-inflammatory and immunomodulatory activity. However, little is known about the role of taurine in schistosome egg-induced granuloma formation and fibrosis. We aimed to evaluate the therapeutic potential of taurine as preventative treatment for Schistosoma japonicum infection. Mice infected with S. japonicum cercariae were supplied with taurine drinking water (1% w/v) for 4 weeks starting at 4 weeks post-infection. Taurine supplementation significantly improved the liver pathologic findings, reduced the serum levels of aminotransferases and area of hepatic granuloma, and prevented fibrosis progression. In addition, taurine decreased the expression of the granulomatous and fibrogenic mediators transforming growth factor β1, tumor necrosis factor α, monocyte chemotactic protein 1α and macrophage inflammatory protein 1α as well as the endoplasmic reticulum stress marker glucose-regulated protein 78. Thus, taurine can significantly attenuate S. japonicum egg-induced hepatic granuloma and fibrosis, which may depend in part on the downregulation of some relevant cytokine/chemokines and reducing the endoplasmic reticulum stress response.

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Taurine has potential as preventative & therapeutic treatment for schistosomiasis.

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Taurine reduced the development of liver pathology caused by S. japonicum infection.

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Taurine attenuated S. japonicum egg-induced hepatic granuloma and fibrosis.

Experimental models of liver fibrosis

Hepatic fibrosis is a wound healing response to insults and as such affects the entire world population. In industrialized countries, the main causes of liver fibrosis include alcohol abuse, chronic hepatitis virus infection and non-alcoholic steatohepatitis. A central event in liver fibrosis is the activation of hepatic stellate cells, which is triggered by a plethora of signaling pathways. Liver fibrosis can progress into more severe stages, known as cirrhosis, when liver acini are substituted by nodules, and further to hepatocellular carcinoma. Considerable efforts are currently devoted to liver fibrosis research, not only with the goal of further elucidating the molecular mechanisms that drive this disease, but equally in view of establishing effective diagnostic and therapeutic strategies. The present paper provides a state-of-the-art overview of in vivo and in vitro models used in the field of experimental liver fibrosis research.

iTRAQ-based proteomic analysis of combination therapy with taurine, epigallocatechin gallate, and genistein on carbon tetrachloride-induced liver fibrosis in rats

Combination therapy with taurine, epigallocatechin gallate, and genistein was effective in alleviating the progression of liver fibrosis in our previous study. To better understand the anti-fibrotic mechanisms of combination therapy, an iTRAQ-based proteomics approach was used to study the expression profiles of proteins in carbon tetrachloride-induced liver fibrosis rats following combination therapy. The anti-fibrotic effects of combination therapy were assessed directly by liver histology, and indirectly by measurement of serum biochemical markers and antioxidant enzymes. The results showed that combination therapy could significantly improve the liver function, as indicated by decreasing levels of alanine aminotransferase (ALT), aspartate transaminase (AST), transforming growth factor-β1 (TGF-β1), and collagen I, increasing levels of total antioxidative capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), and reducing the pathological tissue damage. A total of 89 differential expressed proteins in response to combination therapy were identified by iTRAQ, which were interacted with each other and involved in different biological processes and pathways. Four differentially expressed proteins (Tpi1, Txn1, Fgb, and F7) involved in antioxidant defense system, glycolysis pathway and coagulation cascade pathway were validated by enzyme-linked immunosorbent assay. Our work provided valuable insights into the molecular mechanism of combination therapy against liver fibrosis, and the identified targets may be useful for treatment of liver fibrosis in future.

Inhibition of ASICs reduces rat hepatic stellate cells activity and liver fibrosis: an in vitro and in vivo study

Hepatic fibrosis is a chronic inflammation-associated disease, which is involved in the infiltration of inflammatory cells and releasing of proinflammatory cytokines. In the pathological process, protons are released by damaged cells and acidosis is considered to play a critical role in cell injury. Although the underlying mechanism (s) remain ill-defined, ASICs (acid-sensing ion channels) are assumed to be involved in this process. The diuretic, amiloride, is neuroprotective in models of cerebral ischemia, a property attributable to the inhibition of central ASICs by the drug. However, the effect of inhibition of ASICs by amiloride in the liver fibrotic process remains unclear. We found that amiloride (25, 50, or 100 μM) could restrain acid-induced HSCs at pH6 in vitro. In vivo experiments showed that amiloride could significantly alleviate liver injury, decreasing levels of profibrogenic cytokines, collagen deposition, and reducing pathological tissue damage. In summary, amiloride inhibits hepatic fibrosis in vivo and in vitro, which is probably associated with the downregulation of ASICs.